The aerobic biological treatibility of a high strength mixed petrochemical industrial sludge

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The aerobic biological treatibility of a high strength mixed petrochemical industrial sludge

Author:

Whalen, Thomas F.

Degree

Master of Applied Science - MASc

Program

Civil Engineering

Copyright Date:

1995

Abstract:

Investigations were performed on the aerobic biological
degradation potential of a high-strength, industrial sludge from
the Chatterton Petrochemical site in Delta, BC. The sludge was
located at the bottom of one of the wastewater treatment
equalization lagoons. The lagoon was used to store process water
and on site drainage from the Phenol processing plant operations.
The plant had been in operation from 1961 to 1991. The sludge
contained high concentrations of: Phenol, Diphenyl, Diphenyl
Ether, Diphenyl Methane and Xylene and had a Total COD of over
250 000 mg/L. It also contained over 1000 mg/L of copper and
cobalt.
Treatment was initially attempted using a Modified Batch Process
(MBP). Nine batches were run, to determine the best initial
sludge loading level in the treatment system and to assess the
degree of treatability of the waste mixture. In each set of
experiments, a control was run to determine the degree of
volatilization of the organic compounds from the waste. Twenty
litre batches, having been diluted up to ten times, were run for
more than forty days. In later batches, due to microorganism
growth problems, both ammonia and phosphorus were added to the
system; phosphorus was needed both for the growth of
microorganisms and the precipitation of dissolved copper. The
performance of the systems was monitored using Total COD, Total
BOD and the concentration of selected target organics present in
the mixture.
The most notable batch data resulted from a reactor loaded with
an initial Total COD of approximately 30 000 mg/L. All the
organic compounds of the sludge were removed from the mixture to
below the detection limit of the Gas Chromatograph and the Total
B0D was reduced to a negligible concentration. The success of
the run was attributed, in part, to the high concentration of
phosphorus present in the system. The concentration was 100 mg/L
higher than the nutrient requirements of the culture and the
elevated nutrient loading apparently resulted in the
precipitation of much of the dissolved copper present in the
reactor.
The control showed that when the system was run under ideal
conditions, the loss due to volatilization could be limited to
less than 5%, based on Total COD.
The system was then modified to operate as a True Batch Process
(TBP). Treatment was attempted by keeping 75% of the previous
run's final product in the reactor, while inputting a new load of
sludge and dilution water to make up the volume difference.
Results from the run indicated that treatment kinetics of the new
system were three time faster than the best batch run based on
Total BOD degradation. All of the organic compounds had been
removed to below the detection limit of the Gas Chromatograph in
the end product sludge. However, questions remained about the
accumulation of copper in a true batch treatment system.
Pretreatment of the sludge to remove copper may be necessary to
achieve the high Total BOD removal rates seen in the true batch
system.